Aqueous silicone emulsion for coating woven or non-woven fibrous substrates

ABSTRACT

An aqueous polyorganosiloxane (POS) emulsion which can easily be deposited on/applied to a fibrous substrate at high speed and at limited deposition rates, for example less than 40 g/m 2 . The emulsion contains (A) a POS with ≡Si-vinyl units, (B) a POS with ≡SiH units, (C) an adhesion promoter, (D) a catalyst, (E) at least one surfactant, (F) optionally a POS resin with ≡Si-vinyl units, (G) optionally a crosslinking inhibitor, (H) optionally a pH fixing agent, (I) optionally a formulating additive, (J) optionally a filler, and (K) water. Adhesion promoter (C) is selected from protective hydrocolloids, hydroxylated silanes and/or POS carrying at least one hydroxyl group and at least one salified amino group per molecule, and mixtures thereof, and is present in the range from 0.005 to 10% by weight, based on the silicone phase. Also disclosed is the corresponding coating process and the coated substrate.

The present invention relates to an aqueous emulsion ofpolyorganosiloxane (POS), especially for coating woven (textile) ornon-woven substrates, which is intended to produce an elastomer aftercrosslinking in a thin layer, to a corresponding coating process and tothe coated substrates.

The role of silicone coatings is especially that of binders forimproving the mechanical properties of fibrous substrates and notablythe tear strength, the fraying resistance, the flexibility or thecrumpling ability.

Silicone coatings can also contribute towards giving fibrous substratesa degree of impermeability and a water-repellent character.

In the case of flame-retardant (woven or non-woven) fibrous substratessuch as glass fabrics or nonwovens, it is important that these siliconecoatings do not adversely affect the combustion resistance or, moreespecially, the calorific value of such substrates.

Apart from protecting textile materials against heat and fire, siliconecoatings can also provide them with protection against other aggressionsand/or give them specific properties for certain applications (e.g.dielectric properties). Applications which may be mentioned inparticular are inflatable bags used for protecting vehicle occupants, orairbags, glass braiding (glass fabric sheathing for the thermal anddielectric protection of electric wire), conveyor belts, fire-resistantfabrics or thermal insulators, compensators (leaktight flexible sleevesfor piping), clothing, or flexible materials for use in interior orexterior textile architecture (tarpaulins, tents, stalls, marquees,false ceilings, etc.) or solar protection.

There are several important technical problems associated with theproduction of elastomer coatings on fibrous substrates.

A first problem relates to the operation involvingdeposition/impregnation of the non-crosslinked silicone composition onthe substrate. It is important that this operation can be carried outeasily, rapidly (industrial rate) and, for obvious economic reasons, atreduced deposition rates (e.g. less than 40 microns).

A second problem lies in the minimum level of adhesion which thesilicone coating must have on the substrate.

A third problem results from the ambition to improve the performancecharacteristics of the silicone elastomer coating from the point of viewof its mechanical properties, its protective function and itshydrophobic and impermeabilizing properties, without adversely affectingthe flame-retardant qualities of certain textile substrates such asglass fabrics.

Consideration of the first of the above-mentioned problems has led thoseskilled in the art to liquid silicone compositions of the aqueoussilicone emulsion type, with or without a filler. It has yet to bediscovered whether these emulsions provide a correct solution to thesecond and third of the problems referred to above.

European patent application EP-A-0 535 649 proposes a composition forcoating inflatable bags, or airbags, comprising:

-   -   a polyorganosiloxane (A) of the POS type, e.g.        α,ω-dimethylhydroxy-siloxy PDMS, as an emulsion in water in the        presence of an anionic emulsifier,    -   an adhesion promoter (B) selected from the group comprising the        reaction product of on the one hand an amino-functional silane        or a hydrolyzate: thereof, and on the other hand an acid        anhydride, an epoxy-functional silane or a hydrolyzate thereof,        and/or an organosilane having an isocyanate radical and a        hydrolyzable radical, or a hydrolyzate thereof (for example        3-aminopropyltriethoxysilane+maleic anhydride),    -   a colloidal silica (C),    -   and a catalyst (D).

This emulsion suffers from the following disadvantages: an inadequate 25compromise in terms of adhesion, reactivity and stability of theemulsions, particularly an inadequate adhesion of the silicone to thesubstrate, and an incompatibility of the silanes and surfactant usedwith polyaddition systems based on oils containing ≡SiH and on platinumcatalyst.

Likewise, European patent application EP-A-0 552 983 describes a 30composition of the same type obtained from (A) an organopolysiloxanehaving at least two alkenyl groups[alpha,omega-dimethylvinylsiloxypoly(dimethyl)-(vinylmethyl)siloxane],(B) an organohydrogenopolysiloxane[alpha,omega-tri-methylsiloxypoly(methylhydrogeno)siloxane] having atleast three hydrogen atoms, (C) a platinum crosslinking catalyst, (D) acrosslinking inhibitor of the ethynyl-cyclohexanol type, (E) an adhesionpromoter of the epoxidized trialkoxysilane or amino-functional silanetype (p. 4, line 34) and (F) optionally a reinforcing filler such as acolloidal silica, by emulsification in water in the presence of anemulsifier (dodecylbenzenesulfonate and polyvinyl alcohol, PVA).

This emulsion suffers from the following disadvantages: an inadequatecompromise between adhesion (to the substrate) and stability (of theemulsion); in particular, the use of dodecylbenzenesulfonate andnon-salified amino-functional silane results in a limited stability ofpolyaddition emulsions.

European patent EP-B-0 758 666 relates to aqueous emulsions comprising:

-   -   1—POS of the polydimethylsiloxane (PDMS) type vinylated at the        end of the chain (vinyldimethylsiloxy);    -   2—hydrogenated POS of the        α,ω-trimethylsiloxypoly(methylhydrogeno)-(dimethyl)siloxane        type;    -   3—a platinum catalyst of the Karstedt platinum type;    -   4—an adhesion promoter produced by reacting a        vinyltriacetoxysilane and a trimethoxysilane functionalized with        a glycidyl radical;    -   5—a crosslinking inhibitor of the ethynylcyclohexanol type;    -   6—a silicone resin of the type MT, where M=(Me₃SiO_(1/2)) and        T=(MeSiO_(3/2));    -   7—an emulsifier of the sodium dodecylbenzenesulfonate type.

This polyaddition silicone solution is preferentially applied in theproduction of textile coatings (airbag: polyamide substrate).

European patent application EP-A-1 010 721 relates to the same emulsionas that described in EP-B-0 758 666 except that it has a furtheradditive consisting of carbon black.

Patent application FR-A-2 738 830 relates to an aqueouspolyorgano-siloxane emulsion for coating textile material. This emulsionis obtained by mixing an emulsion A and an emulsion B.

-   Emulsion A comprises:    -   1—POS oil of the α,ω-dimethylvinylsiloxy PDMS type;    -   2—a hydrogenated POS oil of the α,ω-dimethylhydrogenosiloxy PDMS        type;    -   3—a hydrogenated POS silicone oil of the        poly(dimethyl)(methyl-hydrogeno)siloxane type;    -   4—an adhesion promoter of the following types:        vinyltrimethoxysilane, 3-glycidoxypropyltrrmethoxysilane        (GLYMO), 4-epoxycyclohexylethyltrimethoxysilane, chelates of the        butyl orthotitanate type or, finally, in the case of silicone        compositions crosslinkable by polyaddition, aminosilanes of the        amino-functional trimethoxysilane or triethoxysilane type;    -   5—a crosslinking inhibitor of the ethynylcyclohexanol type;    -   6—and fillers=colloidal silica hydrophobized in silicone oil.-   Emulsion B comprises:    -   1′—α,ω-divinylated POS oil identical to that of emulsion A;    -   4′—an adhesion promoter of the butyl titanate type;    -   7—a platinum catalyst;    -   6′—colloidal filler of the same type as in emulsion A.

Emulsions A and B are prepared by mixing (without emulsifying) on theone hand components 1 to 6 and on the other hand components 1′, 4′, 7and 6′, respectively, and then emulsifying the compositions describedabove by agitating them in the presence of water and polyvinyl alcohol(PVA Rhodoviol® 25/140). Once they have been obtained separately,emulsions A and B are mixed with one another.

This aqueous silicone emulsion additionally has the followingdisadvantages: very coarse emulsions are produced, the process is ratherinflexible and burdensome because intermediate silicone mixtures have tobe produced, and it is difficult to prepare very concentrated emulsions.

Given this state of the art, one of the essential objects of the presentinvention is to provide a silicone emulsion, crosslinkable bypolyaddition, for coating woven or non-woven fibrous substrates, saidemulsion possessing rheological properties such that it can easily bedeposited on/applied to the fibrous substrate at high speed and atlimited deposition rates, for example of less than 40 g/m².

Another essential object of the invention is to provide an aqueoussilicone emulsion, crosslinkable by polyaddition, for forming protectivethin coatings (thin layers) on woven (textile) or non-woven fibroussubstrates, the composition of this emulsion being such as to optimizethe adhesion of the crosslinked silicone elastomer film to thesubstrate.

Another essential object of the invention is to provide an aqueoussilicone emulsion, crosslinkable by polyaddition, for coating woven ornon-woven fibrous substrates, the composition of this emulsion beingsuch as to produce a crosslinked silicone elastomer coating capable ofgiving the substrate excellent mechanical qualities (cohesion,flexibility, fraying resistance, tear strength, crumpling ability).

Another essential object of the invention is to provide an aqueoussilicone emulsion that crosslinks by polyaddition to give an elastomercoating for a woven or non-woven fibrous substrate, the composition ofthis emulsion being such as to satisfy the specifications of easydeposition in a limited amount, adhesion to the substrate, andmechanical quality.

Another essential object of the invention is to provide an aqueoussilicone emulsion, crosslinkable by polyaddition, for forming, onmineral fibrous substrates of low adhesiveness (particularly textile ornon-textile glass fiber substrates), silicone coatings that adhere tothe fibers but give them anti-adhesion, hydrophobic and impermeableproperties and satisfy the specifications of easy deposition in alimited amount, adhesion to substrates, mechanical properties(flexibility/tear strength and fraying resistance) and incombustibilitycorresponding to a gross calorific value (GCV), measured according toNFP 92510, below 4200 kJ/kg and preferably below 2500 kJ/kg.

Another essential object of the invention is to provide an aqueoussilicone emulsion that crosslinks by polyaddition, on woven or non-wovenfibrous substrates, to give protective, impermeable, flame-retardant,flexible, strong and optionally flame-retardant elastomer coatings, thecomposition of this emulsion being such that, in the case of glass fibersubstrates, the elastomer film is a good binder capable of giving thecoated glass substrates stability, cohesion and flexibility, while atthe same time minimizing the phenomenon of creasing.

Another essential object of the invention is to produce emulsions thatare chemically stable (preservation of the -SiH and the reactivity) andphysically stable (limited creaming and coalescence during storage ofthe emulsion) and have good characteristics in terms of reactivity(crosslinking by polyaddition) and adhesion to the substrate, by dryingthe treated fabric.

These and other objects are achieved by the present invention, whichrelates first and foremost to an aqueous polyorganosiloxane (POS)emulsion, crosslinkable to an elastomer by means of polyadditionreactions, for impregnating woven or non-woven fibrous substrates, saidemulsion comprising:

-   -   (A) at least one POS having at least two unsaturated functional        groups of the C₂-C₆ alkenyl type bonded to the silicon in each        molecule,    -   (B) at least one POS having at least three hydrogen atoms bonded        to the silicon in each molecule,    -   (C) at least one special adhesion promoter,    -   (D) at least one catalyst,    -   (E) at least one surfactant,    -   (F) optionally at least one POS resin containing at least two        alkenyl groups,    -   (G) optionally at least one crosslinking inhibitor,    -   (H) optionally at least one pH fixing agent,    -   (I) optionally at least one formulating additive,    -   (J) optionally a filler,    -   (K) and water,

-   characterized in that:    -   the adhesion promoter (C) is selected from the group of        compounds comprising protective hydrocolloids, hydroxylated        silanes and/or POS carrying at least one hydroxyl group and at        least one salified amino group per molecule, and mixtures        thereof,    -   the percentage by weight of the adhesion promoter (C), based on        the silicone phase, is such that:        0.005≦(C)≦10        preferably 0.03≦(C)≦5        and particularly preferably 0.05≦(C)≦4.0    -   with the proviso that, when the emulsion comprises at least one        protective hydrocolloid, it is obtained by:        -   directly preparing at least one pre-emulsion that is            non-catalyzing, i.e. devoid of catalyst (D)), and at least            one pre-emulsion that is catalyzing, i.e. contains catalyst            (D), at least one of these pre-emulsions being obtained by            bringing at least part of the silicone phase and at least            part of the protective hydrocolloid into contact with water,        -   and then mixing the catalyzing emulsion(s) with the            non-catalyzing pre-emulsion(s) when the impregnating bath is            made up.

According to one particular characteristic of the invention, theemulsion is devoid of:

-   -   substantially linear, vinylated polydiorganosiloxane        copolymer(s) of the random type, blocked at each end of its        polymer chain by vinyldiorganosiloxy or triorganosiloxy groups        and containing at least three SiVi groups per molecule,    -   and/or vinylated cyclotrisiloxanie(s) of the formula        [R(CH₂═CH)SiO]₃; in which R is a C₁-C₄ alkyl radical, a phenyl        radical or a 3,3,3-trifluoropropyl radical, this vinylated        cyclotrisiloxane being present in an amount such that 0.5 to 60%        and preferably 1.5 to 20% of the number of vinyl groups in the        emulsion consist of the vinyls of this 20 vinylated        cyclotrisiloxane,    -   and/or sodium laurylsulfate.

Preferably, the ratio amount by weight of adhesion promoter (C)/surfacearea developed by the substrate ranges from 0.1I to 10 mg/m² andpreferably from 25 0.2 to 5 mg/m².

“Surface area developed by the substrate” is understood according to theinvention as meaning the surface area developed by the fibers thatconstitute the fabric and are to be covered with the emulsion.

The aqueous silicone emulsion according to the invention is of the typethat crosslinks by polyaddition at room temperature (EVF or RTV), itbeing known that this platinum-catalyzed crosslinking can be thermallyactivated (100-200° C.).

This aqueous silicone emulsion according to the invention adheres tonumerous woven or non-woven fibrous substrates, for example made ofglass fibers or optionally of synthetic textile fibers of the polyesteror polyamide type.

As regards fibrous substrates of the glass fabric type, the emulsionaccording to the invention makes it possible to obtain glass fabricscoated with thin layers of silicone elastomers that are hydrophobic andhave good mechanical properties of flexibility, tear strength andfraying resistance and do not release much heat on combustion: GCV≦4500kJ/kg, preferably GCV≦2500 kJ/kg.

One of the essential constituents of the emulsion according to theinvention is the special adhesion promoter (C), which is carefullyselected so that the adhesion is provided by:

-   -   at least one protective hydrocolloid, preferably PVA, which can        also act as a surfactant (E), either on its own or in        combination with other emulsifiers,    -   or specific, carefully selected silanes and/or POS, namely        silanes and/or POS with hydroxyl and salified amino units,    -   or a protective hydrocolloid, preferably PVA, and silanes and/or        POS with hydroxyl and salified amino units.

In a first embodiment of the invention, the protective hydrocolloidused, preferably PVA, is exclusively dedicated to the function ofadhesion promoter (C).

In a second embodiment of the invention, the surfactant (E) can consistat least in part of at least one protective hydrocolloid, preferably aPVA.

In the first embodiment, the protective colloid, preferably PVA, ispresent in a reduced amount in the emulsion so that it can only fullyexert its function of adhesion promoter (C) and imperfectly its functionof emulsifier. Consequently, the emulsion has to comprise a mainemulsifier or surfactant (E).

In the second embodiment of the invention, the protective colloid,preferably PVA, as adhesion promoter and emulsifier, is present in anamount of 1.5 to 7% of dry PVA, based on the total weight of siliconeoils.

From the qualitative point of view, it may be indicated that theprotective hydrocolloid is preferably a polyvinyl alcohol (PVA) or amixture of PVA, preferably PVA grades which, in aqueous solution (at 4%and at 20° C.), have a standard dynamic viscosity (η_(sd)) of between 5and 40 mPa·s and preferably of between 10 and 30 mPa·s, and an esternumber greater than or equal to 80, preferably greater than or equal to100 and especially of between 120 and 200.

Preferably, the PVA is used in the form of an aqueous solution with astandard dynamic viscosity (η_(sd)) of between 5 and 40 mPa·s andpreferably of between 10 and 30 mPa·s, and an ester number greater thanor equal to 80, preferably greater than or equal to 100 and especiallyof between 120 and 200.

Polyvinyl alcohols (PVA) are compounds obtained indirectly from theiresters by hydrolysis in an aqueous medium or by alcoholysis in ananhydrous medium. In practice, the esters used as starting materials arecommonly polyvinyl acetates. Generally, lysis of the esters to give thePVA is not complete. Acyl radicals remain in the molecule and theirproportion influences the properties of the PVA, especially itssolubility. One method of defining PVA is therefore based on anindication of the ester number (EN), which is inversely proportional tothe degree of hydrolysis. The EN is measured in a manner known per se byneutralizing any acidity in the polyvinyl alcohol, saponifying the acylgroups and titrating the excess alkalinity.

The polyvinyl alcohols according to the invention are also characterizedby their degree of condensation, which can be evaluated by determiningthe dynamic viscosity of a standard solution (designated by η_(sd) inthe present disclosure), in the knowledge that this variable increaseswith the degree of condensation.

The viscosity η_(sd) corresponds to the coefficient of dynamic viscosityof a 4% by weight aqueous solution of PVA, measured at a temperature of20±5° C. using an Ostwald viscometer.

Other protective hydrocolloids which may also be mentioned arewater-dispersible sulfonated polyesters, especially of the sulfonatedpolyethylene terephthalate type.

Water-dispersible sulfonated polyesters are known and commerciallyavailable products. They can be prepared by co-condensing an organicdiacid (such as a saturated or unsaturated aliphatic diacid, an aromaticdiacid, a diacid having several aromatic rings, an arylaliphaticdiacid), one of its diesters or its anhydride and a sulfonated organicdiacid or one of its diesters with a diol in the presence of a customarypolyesterification catalyst such as tetraisopropyl orthotitanate.

The following may be mentioned as starting monomers commonly used forthe preparation of water-dispersible sulfonated polyesters:

-   -   as organic diacids: saturated or unsaturated aliphatic diacids        and aromatic diacids, such as succinic, adipic, suberic and        sebacic acids, maleic, fumaric and itaconic acids and        orthophthalic, isophthalic and terephthalic acids, the        anhydrides of these acids, and their diesters such as the        dimethyl, diethyl, dipropyl and dibutyl esters, the preferred        compounds being adipic acid and orthophthalic, isophthalic and        terephthalic acids;    -   as sulfonated organic diacids: sodium diacid sulfonates or their        diesters such as dialkylisophthalates and dialkylsulfosuccinates        like sodium dimethylisophthalate-5-sulfonate or sodium        dimethylsulfosuccinate;    -   as diols: aliphatic glycols such as ethylene glycol, diethylene        glycol, dipropylene glycol and higher homologs, butane-1,4-diol,        hexane-1,6-diol, neopentyl glycol, and cycloalkane glycols such        as cyclohexanediol and dicyclohexanediolpropane, the preferably        chosen diols being ethylene glycol and diethylene glycol.

The preferred water-dispersible sulfonated polyesters are those having anumber-average molecular weight of between 10,000 and 35,000, an acidnumber below 5 mg KOH/g and a sulfur content of between 0.8 and 2% byweight and preferably of between 1.2 and 1.8%. Polyesters of this typewhich can be used in particular are the products marketed by RHODIAunder the mark GEROL PS20.

The silanes with hydroxyl and salified amino units which can beconstituent components of the promoter (C) are obtained fromnon-salified precursors; examples of these which may be mentioned aremonoaminotrihydroxymonosilanes such as NH₂(CH₂)₃—Si(OH)₃ optionallyoligomerized by partial condensation of the SiOH groups.

This having been stated, the water-soluble adhesion promoter (C)preferably comprises POS with hydroxyl and salified amino units.

These salified amino-POS constituting the promoter (C) areadvantageously formed of several repeat units of average formula (I)below: $\begin{matrix}{( R^{1} )_{x}( R^{2} )_{y}({OH})_{z}{SiO}_{\frac{4 - {({x + y + z})}}{2}}} & (I)\end{matrix}$in which:

-   -   R¹ is a monovalent group devoid of nitrogen whose nature is        identical or different from one repeat unit to the next and        which is a C₁-C₆ alkyl, an aryl, a C₂-C₈ alkenyl or an acrylate,        each of these groups optionally being substituted;    -   R² is of an identical or different nature from one repeat unit        to the next and has the following formula:        —R⁴—N⁽⁺⁾R⁵R⁶.X⁽⁻⁾        -   R⁴ being an optionally substituted C₁-C₁₀ hydrocarbon            radical,        -   the groups R⁵ and R⁶ being identical or different and            representing hydrogen, an optionally substituted C₁-C₁₀            hydrocarbon radical or —R⁴—NH₃ ⁽⁺⁾.X⁽⁻⁾,        -   or the groups R⁵ and R⁶ being different from hydrogen and            together forming a 5- to 7-membered ring containing at least            one heteroatom, preferably nitrogen or oxygen,        -   and X being a counteranion selected from carboxylates and            halides;    -   x, y and z are positive integers or decimal numbers below 4;    -   and x+y+z<4.

Preferably, the salified amino-POS is a resin having a mean siliconfunctionality greater than 2, corresponding to x+y<2:

-   -   x preferably being <2 and, particularly preferably, 0.1≦x≦1;    -   y preferably being <1.2 and, particularly preferably, 0.1≦y≦1.1.

This corresponds to a POS resin which:

-   -   on the one hand is hydroxylated and comprises siloxy units T and        optionally M and/or D and/or Q, or siloxy units Q and M and/or D        and/or T;    -   and on the other hand carries at least one salified amino unit.

The siloxy units M, D, T and Q of the POS (C) are defined as follows:

-   -   unit M=R₃SiO_(1/2)    -   unit D=R₂SiO_(2/2)    -   unit T=RSiO_(3/2)    -   unit Q=SiO_(4/2)

The radicals R are identical or different and correspond to:

-   -   a radical R¹ as defined above, such as an alkyl radical (e.g.        methyl, ethyl, isopropyl, tert-butyl, n-hexyl), a hydroxyl or an        alkenyl (e.g. vinyl, ally),    -   or a unit R² with a salifiable or salified amino unit, as        defined above.

An example which may be mentioned of a linear hydroxylated POS resinwhich can be used as promoter (C) is polymethylsiloxane of which bothends carry a hydroxyl and in which each silicon atom carries asalifiable or salified amino unit.

The resins selected more particularly are those of the type T(OH),DT(OH), DQ(OH), DT(OH), MQ(OH), MDT(OH) or MDQ(OH) or mixtures thereof.Each OH group in these resins is carried by a silicon atom belonging toa unit D, T or Q.

These resins are products resulting from the condensation(mono-condensation or polycondensation, heterocondensation orhomocondensation) of POS monomers, oligomers or polymers carryingcondensable groups, preferably of a hydroxyl nature.

Apart from these hydroxyls, the promoter (C) carries one or moresalifiable or salified amino units that are identical to or differentfrom one another.

In these units the amine can be primary, secondary or tertiary. Invariants the amine can be included in a ring or in isocyanurate groupsor HALS groups (of the piperidine type or another type).

In terms of the invention the HALS groups can be defined as a cyclichydrocarbon chain (HALS) of the formula

in which:

-   -   the radicals R⁷, which are identical to or different from one        another, are selected from linear or branched alkyl radicals        having from 1 to 3 carbon atoms, and phenyl and benzyl radicals;    -   R⁸ is selected from a hydrogen atom, linear or branched alkyl        radicals having from 1 to 12 carbon atoms, alkylcarbonyl        radicals in which the alkyl radical is a linear or branched        radical having from I to 18 carbon atoms, phenyl and benzyl        radicals and a radical O;    -   t is a number selected from 0 and 1;    -   the radicals R⁷ preferably being methyls, the radical R⁸        preferably being a hydrogen atom or a methyl radical and t        advantageously being a number equal to 1.

The salifiable or salified amino units are advantageously selected so asto be capable of binding to the substrate to which the emulsion isapplied, in order to provide adhesion, without adversely affecting thesolubility in water that is desirable for the promoter (C).

For further details on these promoters (C) of the water-soluble siliconeresin type with hydroxyl and salifiable or salified amino units, and ontheir preparation, reference may be made to patent FR-B-2 753 708 orEuropean patent application EP-A-0 675 128, the contents of which forman integral part of the present disclosure by reference.

Specific examples of salifiable amino units which may be mentioned inparticular are:

-   -   aminopropyl: (H₂N)(CH₂)₃—    -   N-methyl-3-aminopropyl: (H₃CNH)(CH₂)₃—    -   N-aminoethyl-3-aminopropyl: (H₂N)(CH₂)₂NH(CH₂)₃—    -   C₆H₅CH₂NH(CH₂)₂(NH)(CH₂)₃—    -   3-ureidopropyl: (H₂NCONH)(CH₂)₃—    -   3-(4,5-dihydroimidazol-1-yl)propyl:        Optionally, the promoter containing salifiable amino units can        also carry non-aminated groups such as the following:        it being possible for these units to be incorporated by        techniques known to those skilled in the art, especially by the        co-hydrolysis/co-condensation of an aminated alkoxysilane with a        non-aminated alkoxysilane carrying the units described above.

It is also possible to add the alkoxysilanes carrying the non-aminatedunits to the emulsion containing the salified aminosilane.

One of the essential characteristics of the promoter (C) selectedaccording to the invention is to be salified via the amino units asdescribed above, which comprise at least one ≡N⁺.X⁻, where X is acounteranion selected from carboxylates and halides, preferably alactate, an acetate or a chloride.

For the promoter (C) to be salified, it is necessary to ensure that theaqueous continuous phase of the dispersion has a pH such that saidpromoter (C) (preferably a hydroxylated POS resin) is maintained inionized form. The pH is chosen, in a manner known per se, according tothe pKa of the acid corresponding to the counteranion used.

The preferred promoter (C) in the form of a hydroxylated resin isincluded in the aqueous continuous phase of the dispersion, beingsolubilized or finely dispersed therein.

In one variant it is possible to envisage that only part of the promoter(C) is in salified form, the remainder being unsalified.

The invention also covers mixtures of promoters (C) of differentnatures.

The silicone phase of the emulsion according to the invention comprisesPOS for generating the elastomer by crosslinking/curing at roomtemperature (23° C.) according to a polyaddition mechanism. It ispossible to accelerate the crosslinking by thermal activation at atemperature above room temperature. Elastomers that vulcanize in thecold by polyaddition and elastomers that vulcanize under the action ofheat by polyaddition fall within the framework of the invention.

In terms of the invention, the words “silicone phase” are to beunderstood as meaning “non-aqueous phase” in the emulsion.

These polyorganosiloxanes, which are the main constituents of thecompositions according to the invention, can be linear, branched orcrosslinked and can contain hydrocarbon radicals and/or reactive groupssuch as hydroxyl groups, hydrolyzable groups, alkenyl groups, hydrogenatoms, etc. It should be pointed out that organopolysiloxanecompositions are amply described in the literature and especially in thework by Walter NOLL entitled “Chemistry and Technology of Silicones”,Academic Press, 1968, 2nd edition, pages 386 to 409.

More precisely, the POS which are the main constituents of thecompositions according to the invention consist of siloxy units of thegeneral formula $\begin{matrix}{R_{n}^{9}{SiO}_{\frac{4 - n}{2}}} & ({II})\end{matrix}$and/or siloxy units of the formula $\begin{matrix}{Z_{n}R_{y}^{9}{SiO}_{\frac{4 - x - y}{2}}} & ({III})\end{matrix}$

In these formulae the various symbols are defined as follows:

-   the symbols R⁹, which are identical or different, are each a    non-hydrolyzable hydrocarbon group, it being possible for this    radical to be:    -   an alkyl or halogenoalkyl radical having from 1 to 5 carbon        atoms and containing from 1 to 6 chlorine and/or fluorine atoms,    -   cycloalkyl and halogenocycloalkyl radicals having from 3 to 8        carbon atoms and containing from 1 to 4 chlorine and/or fluorine        atoms,    -   aryl, alkylaryl and halogenoaryl radicals having from 6 to 8        carbon atoms and containing from 1 to 4 chlorine and/or fluorine        atoms,    -   cyanoalkyl radicals having 3 or 4 carbon atoms;-   the symbols Z, which are identical or different, are each a hydrogen    atom or an alkenyl group;-   n=an integer equal to 0, 1, 2 or 3;-   x=an integer equal to 0, 1, 2 or 3;-   y=an integer equal to 0, 1 or 2;-   the sum x+y is between 1 and 3.

By way of illustration, the following groups may be mentioned as organicradicals R⁹ directly bonded to silicon atoms: methyl; ethyl; propyl;isopropyl; butyl; isobutyl; n-pentyl; t-butyl; chloromethyl;dichloromethyl; α-chloroethyl; α,β-dichloroethyl; fluoromethyl;difluoromethyl; α,β-difluoroethyl; 3,3,3-trifluoropropyl;trifluorocyclopropyl; 4,4,4-trifluorobutyl;3,3,4,4,5,5-hexafluoropentyl; β-cyanoethyl; β-cyanopropyl; phenyl;p-chlorophenyl; m-chloro-phenyl; 3,5-dichlorophenyl; trichlorophenyl;tetrachlorophenyl; o-, p- or m-tolyl; α,α,α-trifluorotolyl; and xylylssuch as 2,3-dimethylphenyl and 3,4-dimethylphenyl.

Preferably, the organic radicals R⁹ bonded to silicon atoms are methylor phenyl radicals, it optionally being possible for these radicals tobe halogenated, or cyanoalkyl radicals.

The symbols Z can be hydrogen atoms or vinyl groups.

It is possible to use a wide variety of two-component or one-componentorganopolysiloxane compositions that crosslink at room temperature orunder the action of heat by means of polyaddition reactions, essentiallyby the reaction of hydrogenosilyl groups with alkenylsilyl groups,generally in the presence of a metal catalyst preferably based onplatinum, said compositions being described e.g. in patents U.S. Pat.Nos. 3,220,972, 3,284,406, 3,436,366, 3,697,473 and 4,340,709. Theorganopolysiloxanes forming part of these compositions generally consistof pairs based on the one hand on at least one linear, branched orcrosslinked polysiloxane consisting of units (III) in which the radicalZ is an alkenyl group and x is equal to at least 1, optionally inassociation with units (II), and on the other hand on at least onelinear, branched or crosslinked hydrogenopolysiloxane consisting ofunits (III) in which the radical Z this time is a hydrogen atom and x isequal to at least 1, optionally in association with units (II).

As regards the unsaturated polysiloxane constituent containing units(III), this can be an oil having a dynamic viscosity at 25° C. ofbetween 200 and 500,000 mPa·s. A mixture based on the above-mentionedoil and an unsaturated gum having a viscosity greater than 500,000 mPa·sand capable of ranging up to 10⁶ mPa·s can also be used, if required, asthe unsaturated polysiloxane constituent containing units (III).

Preferably, in the case of polyaddition compositions, the emulsionsaccording to the invention also contain at least one non-hydroxylatedsilicone resin (F). These silicone resins are well-known branched POSpolymers that are available commercially. In each molecule they have atleast two different units selected from those of the formulaeR¹⁰SiO_(1/2) (unit M), R¹⁰ ₂SiO_(2/2) (unit D), R¹⁰SiO_(3/2) (unit T)and SiO_(4/2) (unit Q).

The radicals R are identical or different and are selected from linearor branched alkyl radicals, vinyl radicals, phenyl radicals and3,3,3-trifluoropropyl radicals. The alkyl radicals preferably have from1 to 6 carbon atoms inclusive. Alkyl radicals R which may be mentionedmore particularly are methyl, ethyl, isopropyl, tert-butyl and n-hexylradicals.

Advantageously, in emulsions of the polyaddition type, at least some ofthe radicals R¹⁰ are vinyl radicals (Vi content especially between 0.1and 2% by weight). These vinyl groups are carried by the units M, D orT. Examples which may be mentioned are vinylated resins MDQ, such asMD^(Vi)Q, or resins MM^(Vi)Q.

As regards the surfactants (E) other than the protective hydrocolloid(PVA), these can be anionic [except in the case where the emulsioncomprises a salified amine as promoter (C)], cationic or non-ionic; inparticular, they can be one or more polyethoxylated fatty alcohols.Preferably, the surfactants (E) are non-ionic. The role of thesurfactant will be especially to refine the particle size of theemulsion and optionally to improve its stability.

The emulsion according to the invention can also contain otherformulating additives (I) such as a condensation catalyst for promotingthe condensation of the silanols of the salified aminosilane oramino-POS without inhibiting the platinum catalysis (e.g. titanium orzirconium salts or possibly certain tin salts), a bactericide, one ormore mineral or organic pigments and one or more organic thickeners(polyethylene oxide, xanthan gum, hydroxyethyl cellulose, acrylic orcationic polymers, etc.) or mineral thickeners (laponite).

Advantageously, the emulsion according to the invention comprises asystem for maintaining the pH at alkaline values, for example of between7 and 8.

This pH maintenance system can be e.g. sodium bicarbonate.

The agent for fixing and maintaining the pH is preferably a buffersystem comprising HCO₃ ⁻/CO₃ ²⁻ and/or H₂PO₄ ⁻/HPO₄ ²⁻. Thus, to obtainthe desired buffer effect, it will be necessary according to theinvention to introduce an HCO₃ ⁻ and/or H₂PO₄ ⁻ salt such as NaHCO₃and/or Na₂CO₃ and/or NaH₂PO₄ and/or Na₂HPO₄. It is self-evident that anyother salt with a different counteranion (e.g. K) would be suitable.Particularly preferably, the buffer system used in practice consists ofNaHCO₃, which is incorporated into the emulsion.

This makes it possible to stabilize the emulsion or the coating orpadding bath produced by mixing the emulsions. This provision isdescribed in greater detail in patent application FR-A-2 773 166, thecontent of which is included in the present disclosure by reference.

Optionally, the emulsion can contain mineral reinforcing or bulkingfillers preferably selected from combustion silicas and precipitatedsilicas. They have a specific surface area, measured by the BET methods,of at least 50 m²/g, especially of between 50 and 400 m²/g andpreferably greater than 70 m²/g, a mean primary particle size of lessthan 0.1 micrometer (μm) and an apparent density of less than 200g/liter.

These hydrophilic silicas preferably incorporated as such into the(continuous) aqueous phase of the emulsion. In one variant these silicascan optionally be treated with one or more organosilicon compoundsnormally used for this purpose. In another variant the silicas can bepredispersed in silicone oil.

These compounds include methylpolysiloxanes such as hexamethyldisiloxaneand octamethylcyclotetrasiloxane, methylpolysilazanes such ashexamethyldisilazane and hexamethylcyclotrisilazane, chlorosilanes suchas dimethyldichlorosilane, trimethylchlorosilane,methylvinyldichlorosilane and dimethylvinylchlorosilane, andalkoxysilanes such as dimethyldimethoxysilane, dimethylvinylethoxysilaneand trimethylmethoxysilane. This treatment can increase the initialweight of the silicas by up to 20%.

It is also possible to use, in addition to or in place of siliceousfillers, other mineral fillers such as calcium carbonates, groundquartz, calcined clays and diatomaceous earths, optionally in the formof an aqueous dispersion (slurry).

As far as non-siliceous mineral materials are concerned, these can beused as semireinforcing or bulking mineral fillers or mineral fillerswith specific properties. Examples of these non-siliceous fillers, whichcan be used by themselves or in a mixture, are carbon black, titaniumdioxide, aluminum oxide, hydrated alumina, expanded vermiculite,non-expanded vermiculite, calcium carbonate, zinc oxide, mica, talcum,iron oxide, barium sulfate and slaked lime. These fillers have aparticle size generally of between 0.01 and 300 μm and a BET surfacearea of less than 100 m²/g.

In general it is possible to use from 0.5 to 60% by weight andpreferably from 10 to 25% by weight of filler, based on the weight ofthe silicone phase of the formulation.

The composition of the emulsion according to the invention is e.g. asfollows:

-   -   100 parts by weight of an α,ω-divinylated POS oil (A) with a        vinyl group content of between 2 and 100 meq/1 00 g;    -   0 to 150 parts by weight of a dispersion of a reinforcing,        semireinforcing and/or bulking filler (J) in water or in an        α,ω-divinylated POS oil (in an amount of 10 to 60% of filler in        the dispersion);    -   1 to 7 parts by weight of at least one POS oil (B 1) containing        ≡SiH such that the ratio of the number of Si—H groups to the        number of Si-alkenyl groups ranges from 0.4 to 10 and preferably        from 0.6 to 5;    -   0.2 to 5 parts by weight of an adhesion promoter (C), taken in        the dry state;    -   a polyaddition catalyst (D) composed of at least one metal        belonging to the platinum group, in an amount of 2 to 150 ppm of        platinum;    -   0.5 to 10 parts by weight of a surfactant (E);    -   0 to 100 parts by weight of a POS resin (F);    -   0 to 1 part by weight of a crosslinking inhibitor (C);    -   0 to n parts by weight of a pH fixing agent (H), n being such        that the pH is maintained between 7 and 8;    -   0 to m parts by weight of a formulating additive (I);    -   0 to 150 parts by weight of a dispersion of a reinforcing,        semireinforcing and/or bulking filler (J) in an α,ω-divinylated        POS oil, in an amount of 10 to 80% of filler in the dispersion;    -   40 to 2000 parts by weight of water (K) so that the final        emulsion or the bath (produced by mixing several emulsions with        water) used to treat the fabric has; a dry extract of between 5        and 65%.

According to another of its features, the present invention furtherrelates to a process for the preparation of an aqueous POS emulsion asdefined above, characterized in that an emulsion is formed byintroducing the constituents (A) to (K) into the same reactor, exceptfor the catalyst (D), which is emulsified separately and added when theimpregnating bath is made up.

In one preferred modality, applied especially in the case where thespecial promoter (C) contains at least one protective hydrocolloid suchas PVA, the emulsion is obtained by:

-   -   directly preparing at least one pre-emulsion that is        non-catalyzing, i.e. devoid of catalyst (D), and at least one        pre-emulsion that is catalyzing, i.e. contains catalyst (D), at        least one of these pre-emulsions being obtained by bringing at        least part of the silicone phase and at least part of the        protective hydrocolloid into contact with water,    -   and then mixing the catalyzing emulsion(s) with the        non-catalyzing pre-emulsion(s) when the impregnating bath is        made up.

Preferably, the emulsion is produced by mixing pre-emulsions which areeach incapable of crosslinking separately because they do not containall the reactive species and the catalyst (≡SiVi POS+≡SiH POS+platinum)necessary for the polyaddition. It is possible, for example, to producean emulsion containing the ≡SiVi, the ≡SiH and the inhibitor (part A)and a catalyzing emulsion based on platinum and ≡SiVi oil (part B),which will be combined when the coating bath is made up.

This greatly facilitates the preparation of a stable emulsion accordingto the invention which can easily be prepared under industrialconditions. It is possible to envisage using: ingredients (A) and/or (B)and/or (C) in the form of pre-emulsions that may or may not contain theother ingredients (D) to (J).

Thus, in one variant:

-   -   the following pre-emulsions are produced:        -   (i) a non-catalyzing pre-emulsion as the basis of the POS            (A),        -   (ii) a non-catalyzing pre-emulsion as the basis of the            POS (B) (crosslinking emulsion),        -   (iii) a pre-emulsion as the basis of the catalyst (D)            (catalyzing emulsion), consisting e.g. of an aqueous            emulsion of a platinum catalyst diluted in a vinylated            silicone oil;    -   these pre-emulsions are mixed, it being possible for one or        other of the pre-emulsions (i) to (iii) also to contain the        surfactant (E), optionally the POS resin (F), optionally the        crosslinking inhibitor (G) and/or optionally the pH fixing        agent (H) and/or optionally the formulating additive (I).

Preferably, the catalyzing emulsion is added to the other,non-catalyzing silicone pre-emulsions (especially the one based on SiH)when the bath is formulated, prior to application to the fabric.

In advantageous modalities of the invention:

-   -   when the surfactant (E) is used as the only emulsifier, the        emulsion is formed directly or by phase inversion;    -   when (all or part of) a PVA (C) is used as the only emulsifier,        the emulsion is only formed directly.        Direct emulsification consists in pouring the silicone phase        into the aqueous solution containing the surfactant.

Another advantageous modality of the invention can consist inintroducing the adhesion promoter (C), especially the salifiedaminosilane or amino-POS, only when the coating bath is prepared.

Another possibility would be to prepare emulsions A and B orpre-emulsions (i), (ii) and (iii) containing no adhesion promoter, andto make provision for incorporating the latter separately when A and Bor (i), (ii) and (iii) are mixed.

The present invention further relates to a process for the preparationof a fibrous substrate coated with at least one layer of elastomersobtained by crosslinking the aqueous POS emulsion as defined above.

This process comprises the following steps:

-   -   a step in which at least one layer of the emulsion as defined        above is deposited on said fibrous substrate;    -   then a crosslinking step to give a fibrous substrate coated with        a layer of elastomer in such a way that the ratio of the dry        weight of the coating to the weight of the fibrous substrate is        less than 0.2 and preferably between 0.05 and 0.11.

The deposition step is advantageously a coating operation.

The coating step can be carried out especially with a knife,particularly a cylinder knife, an air knife or a belt knife, or bypadding, i.e. squeezing between two rolls, or with a sweeping roll,rotating frame or reverse roll, or by transfer or spraying.

It is possible to coat one or both sides of the textile material, thecoating of both sides advantageously being carried out by padding afterimpregnation of the fabric with the emulsion. After passing between therolls, the fabric is uniformly coated with a thin layer of emulsion.This is followed by drying and crosslinking, preferably by means of hotair or infrared, especially for 30 s to 5 min, at a crosslinkingtemperature not exceeding the degradation temperature of the substrate.

When only one side is coated, it is preferable to use a knife. Theemulsion is deposited continuously on the top side of the fabric andthen passes underneath the knife prior to drying and crosslinking asabove.

Preferably, coating is carried out by:

-   -   immersion of the fibrous substrate in a bath of emulsion as        defined above,    -   mechanical drying, preferably by pressing between rolls,    -   and then crosslinking, preferably with thermal activation when        the crosslinking takes place according to a polyaddition        mechanism.

The layer of elastomer is preferably present in an amount such that theratio of the dry weight of the coating to the weight of the fibroussubstrate is less than 0.2 and preferably between 0.05 and 0.11.

In the case of two-component emulsions, the process comprises a previousstep in which the two components are mixed.

The present invention further relates to any product obtainable bydepositing the emulsion as defined above on a fibroussubstrate—preferably made of glass fibers—after which the POS containedin the emulsion applied to the substrate are crosslinked to anelastomer.

Examples which may be mentioned are inflatable bags used for protectingvehicle occupants, or airbags, glass braiding (glass fabric sheathingfor the thermal and dielectric protection of electric wire), conveyorbelts, fire-resistant fabrics or thermal insulators, compensators(leaktight flexible sleeves for piping), clothing, or flexible materialsfor use in interior or exterior textile architecture (tarpaulins, tents,stalls, marquees, etc.).

Examples of possible fibrous substrates to be coated are woven fabrics,nonwovens or knitted fabrics or, more generally, any fibrous substratecomprising fibers, and/or fibers selected from the group of materialscomprising glass, silica, metals, ceramic, silicon carbide, carbon,boron, natural fibers such as cotton, wool, hemp or flax, artificialfibers such as viscose or cellulosic fibers, and synthetic fibers suchas polyesters, polyamides, polyacrylics, chlorofibers, polyolefins,synthetic rubbers, polyvinyl alcohol, aramides, fluorofibers, phenolics,etc.

Preferred examples of fibrous substrates which may be mentioned areglass fabrics.

Advantageously, these coated glass fabrics have a good tear strength andfraying resistance. Furthermore, they are flexible and are not subjectto creasing. Also, their gross calorific value (GCV) is less than orequal to 2500 kJ/kg.

The present invention further relates to the use of an emulsion asdefined above, or obtained by the process described above, for coating afibrous substrate, except for any architectural textile.

“Architectural textile” is understood as meaning a woven fabric ornonwoven and, more generally, any fibrous substrate which, aftercoating, is intended to be used in the construction of:

-   -   shelters, mobile structures, textile buildings, partitions,        flexible doors, tarpaulins, tents, stalls or marquees;    -   furniture, cladding panels, advertising screens, windscreens or        filtering panels;    -   solar protections, ceilings and blinds.

The invention will now be described in greater detail with the aid ofnon-limiting Examples.

EXAMPLES Example 1 Preparation of the Emulsions According to theInvention

1.1—Compounds used:

-   -   POS A-1: α,ω PDMS oil having a dynamic viscosity (η_(sd)) of        60,000 mPa·s at 23° C. and containing 0.073% by weight of Vi    -   POS A-2: hydrogenated POS oil containing Me₂SiO and MeHSiO        units, having a viscosity of 25 mPa·s and containing 0.7% by        weight of H    -   Surfactant (E)=either Rhodasurf ROX, an 85% aqueous solution of        an ethoxylated fatty alcohol marketed by RHODIA, or PVA=a 10%        aqueous solution of polyvinyl alcohol 25/140 (viscosity in 4%        solution: 25/ester number: 140) of mark RHODOVIOL®    -   Adhesion promoter (C) and surfactant (E)=PVA    -   Catalyst (D)=Karstedt platinum diluted in a vinylated POS oil        and containing 10% of Pt    -   Resin (F.1)=a 40% solution of resin MD^(Vi)Q in an α,ω PDMS oil        having a dynamic viscosity (η_(s)) of 60,000 mPa·s at 23° C.,        the resin solution containing 0.7% by weight of Vi    -   (G)=ECH: ethynylcyclohexanol

Compositions by weight (in g): PART (B) PART PART (catalyzing (A1) (A2)emulsion) POS (A-1) - vinylated oil 280 280 106 (G) = ECH 0.7 0.7 0Resin (F.1) 280 280 0 Surfactant (E) = 35 — — Rhodasurf ROX (C) + (E) =PVA — 162 56 [Rhodoviol ®: 10% PVA] POS (A-2) - 25 25 0 hydrogenated oilCatalyst (D) containing — — 0.9 10% of Pt Sorbic acid 0.225 0.225 0 100%sodium bicarbonate — — 1.9 Demineralized water 409 270 35 Total 10301018 200 Properties of the final emulsions Mean particle size 0.3 2.92.4 (um) measured on a Coulter LS130 Dry extract (%) (2 g, 1 h 59.6 59.660.9 at 120° C.) SiH/SiVi (molar ratio) 2.07 of the bath obtained bymixing 100 parts by weight of emulsion A + 10 parts by weight ofcatalyzing emulsion B pH of the bath produced between 7 and 8 by mixing100 parts by weight of emulsion A + 10 parts of catalyzing emulsion B

1.2—Procedure for Preparing the Emulsions:

PART (A1):

The Rhodasurf ROX, 35 g of water and the POS (A-1) oil, in which theinhibitor ECH has been dispersed beforehand, are introduced into an IKAlaboratory reactor equipped with a scraping anchor and a base (cooled bycold water circulation). After stirring for 15 min at 80 rpm, aconcentrated oil/water emulsion is obtained which has the appearance ofa viscous gel.

The resin (F.1) is then poured in over 85 min, with stirring (80 rpm),the final temperature being about 30° C. The mean particle size of theemulsion is then 0.28 μm.

Stirring is continued for 30 min and the POS (A-2) oil (hydrogenatedpolydimethylsiloxane oil) is then poured in over 15 min; 80 g of waterare also poured in.

At this stage the mean particle size of the emulsion, characterized onthe Coulter LS130, is 0.29 μm.

The emulsion is diluted by gradually adding the rest of thedemineralized water (i.e. 310 g), followed by the sorbic acid, and thefinal emulsion is transferred to a polyethylene flask.

PART (A2):

The 10% aqueous solution of polyvinyl alcohol (Rhodoviol 25/140) and thesorbic acid are introduced into an IKA laboratory reactor equipped witha scraping anchor and a base (cooled by cold water circulation).

The resin (E.1) is poured in over 170 min, with stirring, the finaltemperature being about 22° C.

The POS (A-1) oil (ViMe₂SiO-blocked polydimethylsiloxane oil having aviscosity of 60,000 mPa·s and containing 0.07% of Vi), in which theethynyl-cyclohexanol (ECH) has been predispersed, is then poured in over150 min, the final temperature reaching 17° C.

At this stage the mean particle size of the emulsion, characterized onthe Coulter LS130, is 5.9 μm.

An Ultra-Turrax rotor-stator (IKA) is then introduced and the emulsionis sheared for 1 h 30:20 min at 16,000 rpm and then for 1 h 10 min at13,000 rpm.T°_(initial)=22.9° C., T°_(final)=28.6° C.

The mean particle size drops to 3 μm.

The POS (A-2) oil (silicone oil containing Me₂SiO_(2/2) and MeHSiO_(2/2)units, having a viscosity of 25 mPa·s and containing 0.7% by weight ofH) is poured in over 20 min; T=24.5° C.

The emulsion is diluted by gradually adding demineralized water over 60min; T°=27.3° C.

PART B:

Emulsion B is produced according to the same protocol as emulsion A2 bypouring the POS-1 oil 621V60000 (in which the catalyst (D) has beenpredispersed) into the 10% aqueous solution of polyvinyl alcohol. Thebicarbonate is added at the end to the diluted emulsion.

PARTS A+B:

100 parts of A1 or A2 are mixed with 10 parts of B, optionally togetherwith diluting water to adjust the viscosity and concentration of thebath (so as to regulate the amount of silicone deposited on the fabric),when the coating bath is made up before being applied to the fabric. ThepH of the bath is between 7 and 8.

Example 2

Process for Application of the Emulsions of Example 1

By padding (squeezing between two rolls).

The fabric arrives vertically between the rolls where the emulsion isdeposited continuously, the fabric being impregnated on both sides as itleaves the rolls. It then passes through an oven for one minute.

The installation operates at 10 m/min. The inlet and outlet temperaturesof the ovens are set at 120 and 160° C., respectively. The pressure onthe squeezing rolls is in the order of 1.5 bar.

The fabrics are weighed before and after coating in order to measure theweight deposited.

Example 3 Process for Application of the Emulsions of Example 1

This Example is identical to Example 2 except that the pressure on thesqueezing rolls is in the order of 1 bar.

The fabrics are weighed before and after coating in order to measure theweight deposited.

Example 4 Process for Application of the Emulsions of Example 1

By padding (squeezing between two rolls).

The fabric is immersed in a trough located upstream from the squeezingrolls and arrives at an angle of 20° between the rolls, which are at asqueezing pressure of 1.5 bars. The fabric then passes through an ovenfor one minute.

The installation operates at 10 m/min. The inlet and outlet temperaturesof the ovens are set at 120 and 160° C., respectively. The fabrics areweighed before and after coating in order to measure the weightdeposited.

Example 5 Validation in Application—Properties Obtained with the Mixtureof Emulsions A2+B (Without Additive)

5.1 Glass Fabric Weighing 350 g/m²

This fabric is coated by the process of Example 4 with an emulsion ofExample 1 (mixture of emulsions A2+B (without additive)).

The dry extract of this bath was adjusted to 55.7% and then to 48%.

Under these conditions 22 g/m², expressed by dry weight, were deposited.

The coated fabric has an attractive appearance.

The gross calorific value, measured according to NFP92-5 10, is 1900kJ/kg.

The fraying resistance is good, as represented by a combing resistance,measured according to DIN54301, of more than 50 N.

5.2 Glass Fabric Weighing 200 g/m²

This fabric is coated by the process of Example 2 with an emulsion ofExample 1 (mixture of emulsions A2+B (without additive)).

The dry extract of this bath was adjusted to 55.7% and then to 42%.

Under these conditions 15 g/m², expressed by dry weight, were deposited.

The coated fabric has an attractive appearance.

The gross calorific value, measured according to NFP92-5 10, is 2150kJ/kg.

The fraying resistance is good, as represented by a combing resistance,measured according to DIN54301, of more than 50 N.

5.3 Glass Fabric Weighing 200 g/m²

This fabric is coated by the process of Example 3 with an emulsion ofExample 1 (mixture of emulsions A2+B (without additive)).

The dry extract of this bath was adjusted to 55.7% and then to 42%.

Under these conditions 12 g/m², expressed by dry weight, were deposited.

The coated fabric has an attractive appearance, particularly on the topside which has received the emulsion.

The gross calorific value, measured according to NFP92-510, is 1800kJ/kg.

The fraying resistance is good, as represented by a combing resistance,measured according to DIN54301, of more than 50 N.

Example 6 Incorporation of the Salified Aminosilane or the PVA intoEmulsion A when the Coating Bath is Made Up

Experiments on the addition of adhesion promoters were carried out inorder to make the emulsions more adhesive on the glass fiber orsynthetic fibers. The water-soluble silanes tested are:

6.1 Comparative Experiment

The promoter is Dynasylan® HS 2926 marketed by Degussa-Sivento,epoxysilane, pH=3, 60% in water:

6.2 Experiment 6.2

Dynasylan® HS 2929 marketed by Degussa-Sivento, condensed and salifiedacrylic aminosilane, pH=4, 60% in water.

6.3 Experiment 6.3

The promoter is Silquest® VS142 marketed by Witco-OSI, aminosilane,pH=12, about 25% in water, which consists of a silane oligomer describedbelow, partially condensed via its SiOH groups.

This silane was used after salification, which was effected byneutralization of the aqueous solution by adding a sufficient amount ofacetic acid to bring its pH to between 6 and 7.

These promoters of experiments 6.1, 6.2 and 6.3 are added directly topart A2 of the emulsion of Example 1 in a proportion of 2% (by dryweight of silane, based on the oil) 24 h before the bath (mixture ofA2+B) is made up. As soon as the bath has been made up, silk screenfabric coating tests and peel tests are performed according to theattached protocol. The results of adhesion to polyester and to glassfabric of the cloth type, expressed as the peel strength (measured inN/(g/m²) by a 180° peel test described below), are shown in FIGS. 1 and2 attached.

FIG. 1 corresponds to a polyester fabric substrate.

FIG. 2 corresponds to a glass fabric substrate.

Note: In both the Figures, the control corresponds to the adhesionresults obtained when the fabric is treated with emulsion 1.2 of Example1 without the incorporation of additional adhesion promoter.

It is pointed out that the salified aminosilanes appreciably improve theadhesion to glass fabric. The salified aminosilane 6.2 also improves theadhesion to polyester fabric.

The 180° peel test on a fibrous substrate is a measure of the adhesionof PA emulsions. The procedure for this test is as follows:

1. Principle

Measurement of the force required to separate 2 strips of substratescoated with the test mixture crosslinked on the fibrous substrates.

2. Reagents

Use of methylene blue to facilitate identification of the superpositionof the two coated strips of fabric (not essential for the measurement).

3. Eguipment

-   1 hot-pressing machine: set the platen temperature to 120° C.-   2 ovens: one at 80° C. and one at 160° C.-   installation for silk screen application (use of a screen of mesh    diameter ˜200 μm).-   1 balance.-   1 LHOMARGY® DY 30 tensile tester.

4. Procedure

a-Preparation of the Test Pieces

Fabric Substrate Used:

Strips of ˜12 by 17 cm are cut out of the fibrous substrate. Tofacilitate this cutting and avoid fraying, the contours marked out onthe fabric are coated with a silicone elastomer that crosslinks rapidlyin the cold (CAF). Small amounts of CAF are therefore deposited with agun and spread along the contours with a spatula. Cutting is easier oncethe CAF is dry.

Preparation of the Mixture:

10 g of part B to 100 g of part A. ˜20 g of mixture are needed toprepare 3 experiments. 1 drop of methylene blue is added to facilitatethe superposition of the two coated sides.

b-Application

Using the silk screen method, two 10 cm by 5 strips of the mixture aredeposited parallel to one another and ˜2 cm apart. The piece ofsubstrate is weighed before and after coating in order to know theamount deposited.

Drying and Crosslinking Under the Press:

5 min at 80° C.,

superposition of the 2 coated sides on top of one another,

5 min under the press at 120° C. (placed between 2 sheets of paper) andat ˜2 tonnes,

5 min at 160° C.

Leave to stand at room temperature for 2 day.

6.4 Application Experiments with Mixtures of part A1+B. A1+B+SalifiedVS142, A1+B+PVA:

These impregnations are carried out on a glass fabric substrate (200g/m²) by padding according to Example 3. The samples are passed throughan oven at 150° C. for 2 min. The weights deposited are comparable andrepresentative.

The combing resistance tests are performed in order to determine theability of the samples to resist fraying. Combing resistance Part Weightdeposited (DIN54301) A1 + B 18-20 11 A1 + B + salified VS142 18 44 A1 +B + 1.8% PVA 19-20 24 A1 + B + 3.6% PVA 17 14 A1 + B + 5.4% PVA 16-19 16

It could be observed that the best fraying resistance, as represented bythe combing test, was obtained with the composition A1+B+VS142 (presenceof the salified aminosilane).

1. Aqueous polyorganosiloxane (POS) emulsion, crosslinkable to anelastomer by means of polyaddition reactions, for impregnating woven ornon-woven fibrous substrates, said emulsion comprising: (A) at least onePOS having at least two unsaturated functional groups of the C₂-C₆alkenyl type bonded to the silicon in each molecule, (B) at least onePOS having at least three hydrogen atoms bonded to the silicon in eachmolecule, (C) at least one special adhesion promoter, (D) at least onecatalyst, (E) at least one surfactant, (F) optionally at least one POSresin containing at least two alkenyl groups, (G) optionally at leastone crosslinking inhibitor, (H) optionally at least one pH fixing agent,(I) optionally at least one formulating additive, (J) optionally afiller, (K) and water, the adhesion promoter (C) is selected from thegroup of compounds comprising protective hydrocolloids, hydroxylatedsilanes and/or POS carrying at least one hydroxyl group and at least onesalified amino group per molecule, and mixtures thereof, the percentageby weight of the adhesion promoter (C), based on the silicone phase, issuch that:0.005≦(C)≦10preferably 0.03≦(C)≦5and particularly preferably 0.05≦(C)≦4.0 with the proviso that, when theemulsion comprises at least one protective hydrocolloid, it is obtainedby: directly preparing at least one pre-emulsion that is non-catalyzing,i.e. devoid of catalyst (D), and at least one pre-emulsion that iscatalyzing, i.e. contains catalyst (D), at least one of thesepre-emulsions being obtained by bringing at least part of the siliconephase and at least part of the protective hydrocolloid into contact withwater, and then mixing the catalyzing emulsion(s) with thenon-catalyzing pre-emulsion(s) when the impregnating bath is made up. 2.Emulsion according to claim 1, wherein it is devoid of: substantiallylinear, vinylated polydiorganosiloxane copolymer(s) of the random type,blocked at each end of its polymer chain by vinyldiorganosiloxy ortriorganosiloxy groups and containing at least three SiVi groups permolecule, and/or vinylated cyclotrisiloxane(s) of the formula[R(CH₂═CH)SiO]₃, in which R is a C₁-C₄ alkyl radical, a phenyl radicalor a 3,3,3-trifluoropropyl radical, this vinylated cyclotrisiloxanebeing present in an amount such that 0.5 to 60% and preferably 1.5 to20% of the number of vinyl groups in the emulsion consist of the vinylsof this vinylated cyclotrisiloxane, and/or sodium laurylsulfate. 3.Emulsion according to claim 1, wherein the ratio of the amount by weightof adhesion promoter (C) to the surface area developed by the substrateranges from 0.1 to 10 mg/m² and preferably from 0.2 to 5 mg/m². 4.Emulsion according to claim 1, wherein the adhesion promoter (C)comprises a polyvinyl alcohol (PVA).
 5. Emulsion according to claim 1,wherein the surfactant (E) at least partially comprises PVA.
 6. Emulsionaccording to claim 1, wherein the PVA is used in the form of an aqueoussolution having a standard dynamic viscosity (η_(sd)) of between 5 and40 mPa·s and preferably of between 10 and 30 mPa·s, and an ester numbergreater than or equal to 80, preferably greater than or equal to 100 andespecially of between 120 and
 200. 7. Emulsion according to claim 1,wherein the salified amino-POS constituting the promoter (C) is formedof several repeat units of average formula (I) below: $\begin{matrix}{( R^{1} )_{x}( R^{2} )_{y}({OH})_{z}{SiO}_{\frac{4 - {({x + y + z})}}{2}}} & (I)\end{matrix}$ in which: R¹ is a monovalent group devoid of nitrogenwhose nature is identical or different from one repeat unit to the nextand which is a C₁-C₆ alkyl, an aryl, a C₂-C₈ alkenyl or an acrylate,each of these groups optionally being substituted; R²is of an identicalor different nature from one repeat unit to the next and has thefollowing formula:—R⁴—N⁽⁺⁾R⁵R⁶.X⁽⁻⁾ R⁴ being an optionally substituted C₁-C₁₀ hydrocarbonradical, the groups R⁵ and R⁶ being identical or different andrepresenting hydrogen, an optionally substituted C₁-C₁₀ hydrocarbonradical or —R⁴—NH₃ ⁽⁺⁾.X⁽⁻⁾, or the groups R⁵ and R⁶ being differentfrom hydrogen and together forming a 5- to 7-membered ring containing atleast one heteroatom, preferably nitrogen or oxygen, and X being acounteranion selected from carboxylates and halides; x, y and z arepositive integers or decimal numbers below 4; and x+y+z<4.
 8. Emulsionaccording to claim 7, wherein the salified amino-POS is a resin having amean silicon functionality greater than 2, corresponding to x+y<2: xpreferably being <2 and, particularly preferably, 0.1≦x≦1; y preferablybeing <1.2 and, particularly preferably, 0.1≦y≦1.1.
 9. Emulsionaccording to claim 1, wherein it comprises: 100 parts by weight of anα,ω-divinylated POS oil (A) with a vinyl group content of between 2 and100 meq/100 g; 0 to 150 parts by weight of a dispersion of areinforcing, semireinforcing and/or bulking filler (J) in water or in anα,ω-divinylated POS oil (in an amount of 10 to 60% of filler in thedispersion); 1 to 7 parts by weight of at least one POS oil (B1)containing ≡SiH such that the ratio of the number of Si—H groups to thenumber of Si-alkenyl groups ranges from 0.4 to 10 and preferably from0.6 to 5; 0.2 to 5 parts by weight of an adhesion promoter (C), taken inthe dry state; a polyaddition catalyst (D) composed of at least onemetal belonging to the platinum group, in an amount of 2 to 150 ppm ofplatinum; 0.5 to 10 parts by weight of a surfactant (E); 0 to 100 partsby weight of a POS resin (F); 0 to 1 part by weight of a crosslinkinginhibitor (G); 0 to n parts by weight of a pH fixing agent (H), n beingsuch that the pH is maintained between 7 and 8; 0 to m parts by weightof a formulating additive (I); 0 to 150 parts by weight of a dispersionof a reinforcing, semireinforcing and/or bulking filler (J) in anα,ω-divinylated POS oil, in an amount of 10 to 80% of filler in thedispersion; 40 to 2000 parts by weight of water (K) so that the finalemulsion or the bath (produced by mixing several emulsions with water)used to treat the fabric has a dry extract of between 5 and 65%. 10.Process for the preparation of an aqueous POS emulsion according toclaim 1, wherein an emulsion is formed by introducing the constituents(A) to (K) into the same reactor, except for the catalyst (D), which isemulsified separately and added when the impregnating bath is made up.11. Process according to claim 10, wherein the aqueous POS emulsion isobtained by: directly preparing at least one pre-emulsion that isnon-catalyzing, i.e. devoid of catalyst (D), and at least onepre-emulsion that is catalyzing, i.e. contains catalyst (D), at leastone of these pre-emulsions being obtained by bringing at least part ofthe silicone phase and at least part of the protective hydrocolloid intocontact with water, and then mixing the catalyzing emulsion(s) with thenon-catalyzing pre-emulsion(s) when the impregnating bath is made up.12. Process according to claim 10, wherein: the following pre-emulsionsare produced: (i) a pre-emulsion as the basis of the POS (A), (ii) apre-emulsion as the basis of the POS (B) (crosslinking emulsion), (iii)a pre-emulsion as the basis of the catalyst (D) (catalyzing emulsion),comprising an aqueous emulsion of a type g platinum catalyst predilutedin a vinylated silicone oil; these pre-emulsions are mixed, it beingpossible for one or other of the pre-emulsions (i) to (iii) also tocontain the surfactant (E), optionally the POS resin (F), optionally thecrosslinking inhibitor (G) and/or optionally the pH fixing agent (H)and/or optionally the formulating additive (I), the catalyzing emulsionpreferably being added when the coating bath is formulated.
 13. Processaccording to claim 10, wherein: when the surfactant (E) is used as theonly emulsifier, the emulsion is formed directly or by phase inversion;when (all or part of) a PVA (C) is used as the only emulsifier, theemulsion is only formed directly, direct emulsification comprisingpouring the silicone phase into the aqueous solution containing thesurfactant.
 14. Process according to claim 10, wherein the adhesionpromoter (C) is introduced only when the coating bath is prepared. 15.Use of an emulsion according to claim 1, for coating a fibroussubstrate, except for any architectural textile.
 16. Use of an emulsionobtained by the process according to claim 10 for coating a fibroussubstrate, except for any architectural textile.